Conversion of nitrogen dioxide (NO2) to nitric oxide (NO)

Abstract

Inhalation of low levels of nitric oxide can rapidly and safely decrease pulmonary hypertension in mammals. A nitric oxide delivery system that converts nitrogen dioxide to nitric oxide employs a surface-active material, such as silica gel, coated with an aqueous solution of antioxidant, such as ascorbic acid.

What is claimed is: 
     
       1. A method of delivering nitric oxide to a human comprising converting nitrogen dioxide to nitric oxide by fluidly communicating a gas flow including nitrogen dioxide to a receptacle including an inlet, an outlet, and a surface-active material coated with an aqueous solution of an antioxidant, wherein the antioxidant includes ascorbic acid, alpha tocopherol or gamma tocopherol, wherein the inlet is configured to receive the gas flow and fluidly communicate the gas flow to the outlet through the surface-active material such that nitrogen dioxide in the gas flow is converted to nitric oxide. 
     
     
       2. The method of  claim 1  wherein the surface-active material is saturated with the aqueous solution of the antioxidant. 
     
     
       3. The method of  claim 1  wherein the surface-active material comprises a substrate that retains water. 
     
     
       4. The method of  claim 1  wherein the surface-active material comprises a silica gel. 
     
     
       5. The method of  claim 4  where the silica gel is 35 to 70 sized mesh. 
     
     
       6. The method of  claim 1  wherein the receptacle comprises a cartridge. 
     
     
       7. The method of  claim 1  wherein the antioxidant comprises ascorbic acid. 
     
     
       8. The method of  claim 1  wherein the receptacle is at ambient temperature. 
     
     
       9. The method of  claim 1  wherein the surface-active material is prepared using a solution of ascorbic acid in water. 
     
     
       10. The method of  claim 9  wherein the surface-active material is prepared using a 20% solution of ascorbic acid in water. 
     
     
       11. The method of  claim 9  wherein the surface-active material is prepared using a 25% solution of ascorbic acid in water. 
     
     
       12. The method of  claim 9  wherein the surface-active material is prepared using a 30% solution of ascorbic acid in water. 
     
     
       13. The method of  claim 1  wherein the surface-active material is prepared by soaking the surface-active material in a solution of ascorbic acid in water and air drying the surface-active material before inserting the surface-active material into the receptacle. 
     
     
       14. The method of  claim 1  wherein the surface-active material is prepared by soaking the surface-active material in a solution of ascorbic acid in water and drying the surface-active material with a gas before inserting the surface-active material into the receptacle. 
     
     
       15. The method of  claim 1  wherein the antioxidant comprises alpha tocopherol or gamma tocopherol. 
     
     
       16. The method of  claim 1  wherein the receptacle includes screen and glass wool adjacent to both the inlet and the outlet. 
     
     
       17. The method of  claim 1  wherein the screen and glass wool is soaked in the aqueous solution of antioxidant before being inserted in the receptacle.